Bug

ConditionalPickDeep was incorrectly including keys whose value types are non-object unions (for example string | null) when the Condition is an enum.

This PR fixes the issue in two ways:

1. Makes the condition check non-distributive using tuple wrapping: [Type] extends [Condition].
2. Prevents recursion into non-object unions by using: IsPlainObject<NonNullable<Type[Key]>> extends true

Additional tests were added to cover:

• Enum selection edge case
• Union types that must not recurse
• Nested enum cases
• Verification using Paths<>